1. Field of the Invention
This invention relates to a manufacturing method of a CSP (Chip Size Package) type semiconductor device.
2. Description of the Related Art
The CSP receives attention in recent years as a three-dimensional mounting technology as well as a new packaging technology. The CSP means a small package having about the same outside dimensions as those of a semiconductor die packaged in it.
A BGA type semiconductor device has been known as a type of CSP. A plurality of ball-shaped conductive terminals made of metal such as solder is arrayed in a grid pattern on one principal surface of a package of the BGA type semiconductor device and is electrically connected with the semiconductor die mounted on the other side of the package.
When the BGA type semiconductor device is mounted on electronic equipment, the semiconductor die is electrically connected with an external circuit on a printed circuit board by compression bonding of each of the conductive terminals to each of wiring patterns on the printed circuit board.
Such a BGA type semiconductor device has advantages in providing a large number of conductive terminals and in size reduction over other CSP type semiconductor devices such as an SOP (Small Outline Package) and a QFP (Quad Flat Package), which have lead pins protruding from their sides. The BGA type semiconductor device is used as an image sensor chip for a digital camera incorporated into a mobile telephone, for example.
FIGS. 9A and 9B show an outline structure of a conventional BGA type semiconductor device. FIG. 9A is an oblique perspective figure showing a top side of the BGA type semiconductor device. And FIG. 9B is an oblique perspective figure showing a back side of the BGA type semiconductor device.
A semiconductor die 101 is sealed between a first glass substrate 104a and a second glass substrate 104b through epoxy resins 105a and 105b in the BGA type semiconductor device 100. A plurality of ball-shaped conductive terminals (hereafter referred to as conductive terminals) 111 is arrayed in a grid pattern on a principal surface of the second glass substrate 104b, that is, on a back surface of the BGA type semiconductor device 100. The conductive terminals 111 are connected to the semiconductor die 101 through a plurality of second wirings 109. The plurality of second wirings 109 is connected with first wirings pulled out from inside of the semiconductor die 101, making each of the conductive terminals 111 electrically connected with the semiconductor die 101.
More detailed explanation on a cross-sectional structure of the BGA type semiconductor device 100 is given hereafter referring to FIG. 10. FIG. 10 shows a cross-sectional view of the BGA type semiconductor devices 100 divided along dicing lines into individual dice.
The first wiring 103 is provided on an insulation film 102 on a top surface of the semiconductor die 101. The semiconductor die 101 is bonded to the first glass substrate 104a with the resin 105a. A back surface of the semiconductor die 101 is bonded to the second glass substrate 104b with the resin 105b. One end of the first wiring 103 is connected to the second wiring 109. The second wiring 109 extends from the end of the first wiring 103 to a surface of the second glass substrate 104b. The ball-shaped conductive terminal 111 is formed on the second wiring 109 extended onto the second glass substrate 104b. 